Instruments and methods for minimally invasive tissue retraction and surgery

ABSTRACT

Methods and devices retract tissue for minimally invasive surgery in a patient. A retractor includes a working channel formed by a first portion and a second portion. The first and second portions are movable relative to one another from a first configuration for insertion that minimizes trauma to skin and tissue to an enlarged configuration after insertion to further retract skin and tissue in a minimally invasive manner. Instruments are engageable to the first and second portions and operable to move the first and second portions relative to one another.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 10/180,658 filed on Jun. 26, 2002.

BACKGROUND

[0002] The present invention relates to instruments and methods forperforming tissue retraction and surgeries through the retracted tissuein minimally invasive procedures.

[0003] Traditional surgical procedures for pathologies located withinthe body can cause significant trauma to the intervening tissues. Theseprocedures often require a long incision, extensive muscle stripping,prolonged retraction of tissues, denervation and devascularization oftissue. These procedures can require operating room time of severalhours and several weeks of post-operative recovery time due to thedestruction of tissue during the surgical procedure. In some cases,these invasive procedures lead to permanent scarring and pain that canbe more severe than the pain leading to the surgical intervention.

[0004] The development of percutaneous procedures has yielded a majorimprovement in reducing recovery time and post-operative pain becauseminimal dissection of tissue, such as muscle tissue, is required. Forexample, minimally invasive surgical techniques are desirable for spinaland neurosurgical applications because of the need for access tolocations within the body and the danger of damage to vital interveningtissues. While developments in minimally invasive surgery are steps inthe right direction, there remains a need for further development inminimally invasive surgical instruments and methods.

SUMMARY

[0005] The present invention is directed to methods and instruments forperforming surgery in a patient. One specific application concernsinstruments and methods for tissue retraction in minimally invasivespinal surgery. A further specific application includes instruments forpercutaneous tissue retraction to provide access to a surgical locationin the patient. Another specific application includes surgical methodsperformed through the percutaneously retracted tissue at any location ina patient's body. Other applications of the invention will also beapparent from the following description of the illustrated embodiments.

BRIEF DESCRIPTION OF THE FIGURES

[0006]FIG. 1 is a perspective view of one embodiment retractor in aninsertion configuration.

[0007]FIG. 2 is a perspective view of the retractor of FIG. 1 with firstand second portions of the retractor separated from one another.

[0008]FIG. 3 is a perspective of another embodiment retractor in aninsertion configuration.

[0009]FIG. 4 is a detailed view of one configuration of adjacentretractor portions in an insertion configuration.

[0010]FIG. 5 is a detailed view of another configuration of adjacentretractor portions in an insertion configuration.

[0011]FIG. 6 is a detailed view of another configuration of adjacentretractor portions in an insertion configuration.

[0012]FIG. 7 is a plan view of the retractor of FIG. 1 in an insertionconfiguration with an instrument for separating first and secondportions of the retractor coupled thereto.

[0013]FIG. 8 is a section view through line 8-8 of FIG. 7 in which theretractor has been inserted over sequential tissue dilators.

[0014]FIG. 9 is the retractor of FIG. 8 with the working channel of theretractor enlarged.

[0015]FIG. 10 is a side view of another embodiment retractor in aninsertion configuration.

[0016]FIG. 11 is the retractor of FIG. 10 with the working channelenlarged.

[0017]FIG. 12 is a perspective view of another embodiment retractor andinstrument for separating first and second portions of the retractor.

[0018]FIG. 13 is a perspective view of another embodiment retractor andinstrument for separating first and second portions of the retractor.

[0019]FIG. 14 is a perspective view of another embodiment retractor andinstrument for separating first and second portions of the retractor.

[0020]FIG. 15 is a perspective view of another embodiment retractor inan insertion configuration.

[0021]FIG. 16 is a plan view of the retractor of FIG. 15.

[0022]FIG. 17 is a plan view of the retractor of FIG. 15 with aseparation instrument engaged thereto.

[0023]FIG. 18 is a perspective view of the assembly of FIG. 17.

[0024]FIG. 19 is another perspective view of the assembly of FIG. 17with the retractor portions separated.

[0025]FIG. 20 is a plan view of the assembly of FIG. 19.

[0026]FIG. 21 is a perspective view of the assembly of FIG. 19 withlever arms moved to a pivoting position.

[0027]FIG. 22 is a sectional view of a portion of the separationinstrument through line 22-22 of FIG. 21 showing a lever arm lockingassembly when the retractor portion engaged thereto is in a non-pivotedposition.

[0028]FIG. 23 is perspective view of the separation instrument of FIG.17 detached from the retractor.

[0029]FIG. 24 is an elevation view of a portion of the separationinstrument of FIG. 17.

[0030]FIG. 25 is a perspective view of the assembly showing theretractor portions pivoted.

[0031]FIG. 26 is a sectional view through line 26-26 of FIG. 25 of aportion of the separation instrument showing the lever arm lockingassembly when the retractor portion engaged thereto is in a non-pivotedposition.

[0032]FIG. 27 is a perspective view of the assembly of FIG. 19 showingthe retractor portions pivoted and a first intermediate retractorassembly engaged to the separation instrument.

[0033]FIG. 28 is a plan view of the assembly of FIG. 27.

[0034]FIG. 29 is a perspective view of the assembly of FIG. 27 with asecond intermediate retractor assembly engaged to the first intermediateretractor assembly.

[0035]FIG. 30 is a plan view of the assembly of FIG. 30.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0036] For the purposes of promoting an understanding of the principlesof the invention, reference will now be made to the embodimentsillustrated in the drawings and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the invention is thereby intended. Any such alterationsand further modifications in the illustrated devices and describedmethods, and any such further applications of the principles of theinvention as illustrated herein are contemplated as would normally occurto one skilled in the art to which the invention relates.

[0037] The present invention provides instruments and methods forperforming percutaneous surgery, including spinal surgeries that includeone or more techniques such as laminotomy, laminectomy, foramenotomy,facetectomy, discectomy, interbody fusion, spinal nucleus or discreplacement, and implant insertion, for example. The surgery isperformed through a working channel or passageway through skin andtissue of the patient provided by a retractor. Viewing of the surgicalsite at the working end of the retractor can be accomplished withviewing instruments mounted on the retractor, positioned over theretractor, and/or through a viewing system such as lateral fluoroscopy.The retractor is movable in situ to increase the size of the workingchannel to facilitate access to the working space at the distal end ofthe retractor while minimizing trauma to tissue surrounding theretractor. The retractor can be used with any surgical approach to thespine, including anterior, posterior, posterior mid-line, lateral,postero-lateral, and/or antero-lateral approaches, and in other regionsbesides the spine.

[0038] In FIG. 1 there is illustrated a retractor 20 that includes afirst portion 22 and a second portion 42. First portion 22 has a distalend 24 and an opposite proximal end 26. Second portion 42 has a distalend 44 and an opposite proximal end 46. Distal ends 24, 44 can bebeveled to facilitate insertion, although non-beveled ends are alsocontemplated. First portion 22 can be positioned adjacent to or matedwith second portion 42 along adjacent ones of the longitudinal edges 25of first portion 22 and longitudinal edges 45 of second portion 42. Aworking channel 50 is formed between first portion 22 and second portion42. Working channel 50 extends between and opens at distal ends 24, 44and proximal ends 26, 46.

[0039] Retractor 20 is insertable through skin and tissue of a patientto provide working channel 50 to the surgical site. It is contemplatedthat retractor 20 is inserted through the skin and tissue in aninsertion configuration for working channel 50, such as shown in FIG. 1.In the insertion configuration, working channel 50 is substantiallyenclosed or circumscribed by first portion 22 and second portion 42.After insertion into the patient, working channel 50 can be enlarged byseparating first portion 22 and second portion 42. Separation of firstand second portions 22, 42 increases the size of working channel 50 fromproximal ends 26, 46 to distal ends 24, 44.

[0040] In the insertion configuration of FIG. 1, working channel 50 iscircumscribed or substantially enclosed by first portion 22 and secondportion 42. Working channel 50 can have a size in the insertionconfiguration that allows passage of one or more surgical instrumentsand/or implants to the surgical location in the patient's body. It maybe desirable during surgery to provide greater access to the location inthe patient's body beyond the locations provided through working channel50 in its insertion configuration. First portion 22 and second portion42 are movable away from one another to enlarge working channel 50. Inthe enlarged configuration of working channel 50, a space is formedbetween at least of the adjacent longitudinal edges 25, 45 of first andsecond portions 22, 42. The space between the adjacent longitudinaledges 25, 45 exposes enlarged working channel 50 to skin and tissue ofthe patient between the separated first portion 22 and second portion42. This exposed tissue can also be accessed by the surgeon through theenlarged working channel 50 with one or more instruments and/orimplants. It is further contemplated that a shield, guard or tissueretractor could be placed in enlarged working channel 50 to maintain theexposed tissue away from the enlarged working channel 50.

[0041] First portion 22 includes a semi-cylindrical body 23 extendingbetween distal end 24 and proximal end 26. A collar 28 extends aboutproximal end 26, and forms a lip extending about the outer surface ofbody 23. First portion 22 includes a first bracket member 39 extendingfrom proximal end 26. Second portion 42 includes a semi-cylindrical body43 extending between distal end 44 and proximal end 46. A collar 48extends about proximal end 46 of second portion 42, and defines a lipextending about the outer surface of body 43. Second portion 42 includesa second bracket member 40 extending from proximal end 46.

[0042] A first alignment member 30 can be provided to couple a firstside of first portion 22 to second portion 42 adjacent proximal ends 26,46. A second alignment member 31 opposite first alignment member 30 canbe provided to couple the other side of first portion 22 to secondportion 42 adjacent proximal ends 26, 46 along another side of retractor20. Holding member 38 can be positioned about bracket members 39, 40 tohold first portion 22 and second portion 42 adjacent one another. In oneembodiment, alignment members 30, 31 are pins slidably received in holes43 (only one shown in FIG. 2) formed in the other retractor portion whenretractor 20 is in its insertion configuration. Alignment members 30, 31maintain first portion 22 and second portion 42 in longitudinalalignment with one another during and after insertion. Holding member 38can be resiliently biased to engage bracket members 39, 40 and maintainfirst portion 22 and second portion 42 adjacent one another during andafter insertion. Holding member 38 can be removed from bracket members39, 40 when it is desired to separate first and second portions 22, 42.

[0043] Other arrangements are also contemplated for aligning andreleasably coupling first portion 22 and second portion 42 to oneanother. Examples of such arrangements include dovetail connections,fasteners, threaded coupling members, clamping members, snap rings,compression bands, straps, ball-detent mechanisms, and releasablyinterlocking cams or tabs, for example. Examples of suitable holdingmembers include clamps, clips, bands, straps, hooks, ties, sleeves,coupling members and/or fasteners. As shown in FIG. 3, holding member 38can be provided with a clamping mechanism 35 to bias holding member 38into engagement with bracket members 39, 40. Clamping mechanism 35 caninclude a thumb wheel and threaded shaft that bears against one or bothof the bracket members 39, 40 to solidly attach holding member 38thereto and provide a quick disconnect of holding member 38 from bracketmembers 39, 40.

[0044] Bracket member 39 and 40 can extend from and be integrally formedwith or attached to respective ones of the collars 28, 48 of first andsecond portions 22, 42. Bracket members 39, 40 can also be provided as asingle bracket on one of the collars 28, 48 in lieu of or in addition tobracket members 39, 40. Bracket members 39, 40 extend away from workingchannel 50 and are connectable to one end of a flexible or articulatablearm 41 (FIG. 7.) The opposite end of arm 41 (not shown) can be mountedon the surgical table or other support device. Arm 41 supports retractor20 in the patient yet allows percutaneous manipulation andre-positioning of retractor 20 during surgery. It is furthercontemplated that more than one flexible arm 41 can be provided toengage respective ones of the retractor portions 22, 42 afterenlargement of working channel 50.

[0045] With working channel 50 of retractor 20 in its insertionconfiguration, the opposite edges 25 of first portion 22 are adjacentrespective ones of the opposite edges 45 of second portion 42. Variousinterfaces between the edges 25, 45 are contemplated. For example, inFIG. 4 there is shown a configuration in which edges 25 (only one shown)of first portion 22 abut along all or a portion of the adjacent edge 45of second portion 42 in the insertion configuration for working channel50. In FIG. 5 there is another embodiment first portion 22 having anouter recess 27 along each of the edges 25 (only one shown.) Each of theedges 45 can include an inner recess 47. Edges 25, 45 can thusinterdigitate and abut one another in recesses 27, 47 in the insertionconfiguration for working channel 50. In FIG. 6 there is shown anoverlapping arrangement in which edges 25 (only one shown) of firstportion 22 can be located inside, relative to working channel 50, theadjacent edge 45 of second portion 42. It is also contemplated that edge45 could be located inside edge 25. It is further contemplated that onone side of retractor 20 edge 25 can be inside edge 45, and on the otherside of retractor 20 the other edge 45 can be inside the other edge 25.Other arrangements contemplate a gap between adjacent ones of the edges25, 45.

[0046] Body 23 has a perimeter length along distal end 24 which can beabout the same as the perimeter length of body 23 at proximal end 26.Body 43 of second portion 42 includes a perimeter length along distalend 44 which can be about the same as the perimeter length of body 43adjacent proximal end 46. Bodies 23, 43 can have a semi-circularcross-section, and form a generally circular cross-section for theworking channel when placed adjacent one another, as shown in FIG. 1.Other cross-sectional shapes are also contemplated for first and secondportions 22, 42, such as, for example, any open sided polygonal shape,curved shape, or combined curved/polygonal shape.

[0047] Extending proximally from collar 28 of first portion 22 is afirst engagement member 32 having a head portion 36 forming a recess 33therebelow. Extending proximally from collar 48 of second portion 42 isa second engagement member 52 having a head portion 56 forming a recess53 therebelow. Head portions 36, 56 can be threadingly engaged,reciprocally engaged and spring biased toward collars 28, 48, orotherwise engaged to the respective collar 28, 48 and adjustable toincrease and decrease the height of the respective recess 33, 53 toreceive and couple a separation instrument therein. It is alsocontemplated that engagement members 32, 52 can be non-adjustable, andthe separation instrument configured to engage the adjacent engagementmember 32, 52.

[0048] As discussed further below, an instrument for separating firstportion 22 and second portion 42 can be non-releasably or releasablyengaged to engagement members 32, 52 for application of a separationforce to enlarge working channel 50 by separating first portion 22 andsecond portion 42. Such an instrument could also be releasable ornon-releasably engaged to first portion 22 and second portion 42. Suchan instrument could also maintain first portion 22 and second portion 42in the initial insertion configuration and/or in the enlargedconfiguration for working channel 50. Other means besides the separationinstrument could also be employed for maintaining first portion 22 andsecond portion 42 in one or both of the initial insertion configurationand the enlarged configuration for working channel 50. For example, whenthe separation instrument is not attached, a member could extend betweenand be coupled to each of the engagement members 32, 52 and/or retractorportions 22, 42.

[0049] Engagement members 32, 52 are positioned on lateral extensions29, 49 of collars 28, 48, respectively. Lateral extensions 29, 49 extendfar enough laterally to allow engagement of a separation instrument toengagement members 32, 52 without obstructing working channel 50 withthe separation instrument.

[0050] It is contemplated that body 23 can be provided with a thickness39 (FIG. 4.) Body 43 of second portion 42 can be provided with athickness 59 (FIG. 4) that can be the same, greater than, or less thanthickness 39 of first portion 22. Bodies 23, 43 can be provided withsufficient rigidity between their distal and proximal ends to separateand maintain separation of body tissue when retractor is initiallyinserted and also when tissue is retracted by moving first portion 22and second portion 42 away from one another. First thickness 39 andsecond thickness 59 can provide first portion 22 and second portion 42,respectively, with sufficient rigidity to resist bending or bowing underthe forces exerted on it by the retracted tissue. Also, body 23 has adepth 37 from edges 25 to the midpoint of wall of body 23 extendingbetween edges 25. Depth 37 can provide a sufficient section modulus ormoment of inertia in the direction of movement of first portion 22 toresist bending, bowing and/or deflection forces applied during suchmovement. Similarly, body 43 can have a depth 57 from edges 45 to themidpoint of wall of body 43 extending between edges 45 to provide asufficient section modulus or moment of inertia in the direction ofmovement of second portion 42 to resist bending, bowing, and/ordeflection forces applied during such movement.

[0051] In one specific embodiment, first portion 22 and second portion42 are each made from surgical grade stainless steel. Other materialsare also contemplated for first and second portions 22, 42, including,for example, plastics and metals and metal alloys, such as, for example,spring steel, shape memory metals and alloys, and aluminum.

[0052] In the initial insertion configuration, working channel 50 has agenerally circular cross-section along retractor 20, as shown in FIGS.1, 7 and 8. Working channel 50 has a first width 51 in the direction ofmovement of first portion 22 relative to second portion 42, and a secondwidth 55 extending from one of the pair of adjacent edges 25, 45 to theother of the pair of adjacent edges 25, 45. In the illustratedembodiment, first and second widths 51 and 55 can be substantially thesame since working channel 50 has a generally circular cross-section inits initial insertion configuration. In the enlarged configuration, asshown in FIGS. 2 and 9, second width 55 remains generally the same as inthe initial insertion configuration for retractor 20, while first width51 is increased by separating first portion 22 and second portion 42.

[0053] Various configurations for working channel 50 are contemplated.In the initial insertion configuration, working channel 50 can have acylindrical shape with, for example, a circular, oval, elliptical,polygonal, or combined polygonal/curved cross-sectional shape. In theenlarged configuration, working channel 50 can have a cylindrical orfrusto-conical shape with, for example a cross-section that is oval,elliptical, circular, curved, polygonal, or combined polygonal/curved inshape.

[0054] One specific application for retractor 20 is in spinal surgery.It is contemplated that, after insertion of retractor 20, first portion22 and second portion 42 are separated predominantly in one direction toretract muscle and tissue along pathway 62 (FIG. 7.) For example, firstand second portions 22, 42 of retractor 20 can be primarily orpredominantly separable in the direction of the spinal column axis. Themuscle tissue adjacent the spine has a fiber orientation that extendsgenerally in the direction of the spinal column axis. The separation ofbody portions 23, 43 of retractor 20 can also separate the muscle tissuealong the fibers, thus the amount of separation and the resultanttearing and trauma to the muscle tissue can be minimized. It is alsocontemplated in other techniques employing retractor 20 that workingchannel 50 can be enlarged primarily in a direction other than along thespinal column axis or in areas other than spine. Embodiments ofretractor 20 are also contemplated in which working channel 50 isenlarged substantially in one direction or in all directions.

[0055] Referring now to FIGS. 7-9, one example of a method forpositioning of retractor 20 through the skin 60 and tissue 68 of thepatient will be described. An incision is made in skin 60 adjacent thelocation of a patient's anatomy to be accessed. For example, in spinalsurgery, the incision can be made at a vertebral level at a locationthat provides access to the disc space between adjacent vertebrae or toone or more vertebra through a desired approach. Prior to insertion ofretractor 20, skin 60 and tissue 68 can be sequentially dilated viadilation instrument set 66 which can include guidewires and/or one ormore tissue dilators of increasing size. The tissue dilators areinserted one over another to form a pathway 62 through skin 60 andtissue 68 to the surgical site in the patient. In such procedures,retractor 20 is positioned over the last inserted dilator to formpathway 62 in the skin and tissue. Working channel 50 through retractor20 provides access to a working space 64 at the distal end of retractor20 when the guidewires and dilators, if used, are removed therefrom.

[0056] For the entire surgery or for certain procedures during thesurgery, it may be desired by the surgeon to increase the size ofworking channel 50 to facilitate access working space 64 below thedistal end of retractor 20, or to increase the size of working space 64.First and second portions 22, 42 of retractor 20 can be separated fromtheir insertion configuration to a separated configuration in whichworking channel 50 is enlarged, as shown in FIG. 9. In the enlargedconfiguration, first portion 22 and second portion 42 can be movedlaterally and/or pivoted away from one another by a separationinstrument. One example of a separation instrument is separationinstrument 70 extending between and coupled to engagement members 32,52. Adjacent ones of the edges 25, 45 are separated by a space 69,exposing working channel 50 to the skin and tissue along pathway 62while first and second portions 22, 42 hold tissue out of the operativefield. In the enlarged configuration, working channel 50 and thuspathway 62 are enlarged through the through skin 60 and tissue 68 formedby first portion 22 and second portion 42. The size of working space 64can be increased while minimizing trauma to the tissue and skin alongpathway 62.

[0057] First and second portions 22, 42 can be pivoted or rotated awayfrom one another about their proximal ends to provide working channel 50with a tapered configuration that reduces in size from the distal end ofretractor 20 adjacent working space 64 through skin 60 to the proximalend of retractor 20. A tapered working channel provides the surgeongreater access and increased visualization of working space 64 whileminimizing tissue retraction. The tapered working channel 50 also allowsgreater angulation of instruments and implants placed through workingchannel 50, more selection in positioning of instruments and implantswithin working channel 50, and the ability to position instruments andimplants adjacent the inner wall surfaces of the separated first andsecond portions 22, 42, increasing the room available at working space64 for multiple instruments and for orienting implants.

[0058] Viewing instruments can be positioned in or adjacent to workingchannel 50 to facilitate surgeon viewing of working space 64 and theoperative site. For example, an endoscopic viewing element can bemounted on the proximal end of retractor 20 with a scope portionextending along working channel 50. A microscopic viewing element can bepositioned over the proximal end of retractor 20 for viewing workingspace 64 and the surgical site. Other imaging techniques, such aslateral fluoroscopy, can be used alone or in combination with theendoscopic and microscopic viewing elements. It is further contemplatedthat other instruments can be mounted on the proximal end of retractor20, such as nerve root retractors, tissue retractors, forceps, cutter,drills, scrapers, reamers, separators, rongeurs, taps, cauterizationinstruments, irrigation and/or aspiration instruments, illuminationinstruments, inserter instruments, and the like for use in surgicalprocedures through retractor 20 in the working space. Such viewinginstruments and other instruments can be employed with working channel50 in its initial insertion configuration and/or its enlargedconfiguration.

[0059] Referring now to FIG. 7, further details regarding one embodimentinstrument 70 for separating first and second portions 22, 42 will beprovided. Instrument 70 includes a rack portion 72 and a body portion74. Rack portion 72 includes a foot portion 76 releasably engageable toengagement member 52, and body portion 74 includes a foot portion 78releasably engageable to engagement member 32. Rack portion 72 includesan extension 80 received through a housing 82 of body portion 74.Housing 82 includes a pinion 84 rotatably mounted therein and engagedwith teeth 86 of extension 80. Pinion 84 can be engaged by a tool ormanually by the surgeon and rotated to move rack portion 72 relative tobody portion 74, thereby moving feet portion 76, 78 away from oneanother to separate first portion 22 and second portion 42 to enlargeworking channel 50. A stop member 88 can be provided at the end of or atany position along extension 80 to prevent over-separation of firstportion 22 and second portion 42.

[0060] Referring now to FIGS. 10 and 11, another embodiment retractor 20is shown in which retractor portions 22, 42 are simultaneously separablefrom one another and pivotal relative to one another to enlarge workingchannel 50. Collar 28 includes an extension 300 extending from body 23of first portion 22 generally in the direction of separation of firstportion 22 from second portion 42. Collar 48 includes an extension 302extending from body 43 of second portion 42 generally in the directionof separation of second portion 42 from first portion 22. In theinsertion configuration of FIG. 10, extension 300 extends distally fromcollar 28 at an angle 304, and extension 302 extends distally fromcollar 48 at an angle 306. Engagement members 32, 52 extend proximallyfrom respective ones of the extensions 300, 302.

[0061] In FIG. 11, working channel 50 has been enlarged by applicationof a lateral separation force with, for example, separation instrument70 discussed above or instrument 220 discussed below, as indicated byarrows 312, 314. The lateral separation forces move first portion 22away from second portion 42. The lateral separation forces are appliedto the engagement members 32, 52 on the angled extensions 300, 302.Angled extensions 300, 302 tend to cause distal ends 24, 44 to pivot orrotate away from one another as angled extensions 300, 302 are rotatedor pivoted in the direction in which lateral forces 314, 316 areapplied. As a result, edges 25, 45 form angle 307 therebetween andprovide working channel 50 with an enlarged, frusto-elliptical shapebetween the distal ends 24, 44 and proximal ends 26, 46. Distal ends 24,44 are separated at edges 25, 45 by a distance 308, which is greaterthan the distance 310 separating edges 25, 45 adjacent proximal ends 26,46.

[0062] Referring now to FIG. 12, there is shown retractor 20 withanother embodiment instrument 90 for separating first portion 22 andsecond portion 42. Instrument 90 includes a rotational separator 92 anda lateral separator 110. Rotational separator 92 is operable to rotateor pivot first portion 22 and second portion 42 relative to one anotherabout their proximal ends 26, 46 to move distal ends 24, 44 away fromone another. Lateral separator 110 is operable to move first portion 22and second portion 24 away from one another by separating proximal ends26, 46 and distal ends 24, 44 laterally. As discussed further below,instrument 90 can be coupled to engagement members (not shown) of thefirst and second portions 22, 42 located adjacent one of the edges 25,45 and extending laterally from the respective first and second portions22, 42. Rotational separator 92 and lateral separator 110 can beoperated sequentially to pivot then laterally separate, or laterallyseparate and then pivot first and second portions 22, 42. Rotationalseparator 92 and lateral separator 110 can also be operatedsimultaneously to pivot/rotate and laterally separate first and secondportions 22, 42.

[0063] Rotational separator 92 includes a first handle 94 and a secondhandle 96. First handle 94 is mounted to a first coupling member 98, andsecond handle 96 is mounted to a second coupling member 100. Firstcoupling member 98 of rotational separator 92 is non-rotatably coupledto the lateral engagement member of first portion 22, and secondcoupling member 100 of rotational separator 92 is non-rotatably coupledto the lateral engagement member of second portion 42. First and secondportions 22, 42 are pivotal or rotatable away from one another by movingfirst handle 94 in the direction of arrow 105 toward second handle 96,and by moving second handle 96 in the direction of arrow 106 towardfirst handle 94. Movement of handles 94, 96 in the direction of arrows105, 106 rotates the proximal ends of coupling members 98, 100 towardone another to effect the pivotal or rotational movement of first andsecond portions 22, 42. Handles 94, 96 can be pivotally coupled toconnectors 98, 100 for rotation in the direction of arrow 108 to movehandles 94, 96 away from the proximal end opening of working channel 50and provide the surgeon clear access thereto.

[0064] Lateral separator 110 extends laterally from retractor 20transversely to the direction of separation of first portion 22 andsecond portion 42. Lateral separator 110 includes a first handle 112 anda second handle 114. A first coupling member 116 is pivotally coupled ata mid-portion thereof to first handle 112, and a second coupling member118 is pivotally coupled at a mid-portion thereof to second handle 114.Coupling members 116, 118 are rotationally coupled at their distal endsto respective ones of the lateral engagement members extending fromfirst portion 22 and second portion 42. A first link 120 extends betweenand is pivotally coupled at one end to first handle 112 and at itsopposite end to second coupling member 118. A second link 122 extendsbetween and is pivotally coupled at one end to second handle 114 and atits opposite end to first coupling member 116. First coupling member 116includes a first tab 134 that rotatably receives the lateral engagementmember extending from first portion 22. Second coupling member 118includes a second tab 136 that rotatably receives the lateral engagementmember extending from second portion 42.

[0065] First link 120 includes a first slot 124, and second link 122includes a second slot 126. A locking pin 128 extends through slots 124,126 and couples links 120, 122 to one another. To laterally separatefirst portion 22 from second portion 42, locking pin 128 is loosened sothe links 120, 122 are movable relative to one another. First handle 112is moved in the direction of arrow 130 toward second handle 114, andsecond handle 114 is moved in the direction of arrow 132 toward firsthandle 112. First link 120 pushes outwardly on second coupling member118 while second handle 114 pulls outwardly on second coupling member118. Similarly, second link 122 pushes outwardly on first couplingmember 116 while first handle 112 pulls outwardly on first couplingmember 116. Coupling members 116, 118 thus laterally move away from oneanother. This separates first and second portions 22, 42 such that edges25, 45 are displaced laterally the same relative distance from oneanother between proximal ends 26, 46 and distal ends 24, 44. Locking pin128 can then be threaded to clamp link members 120, 122 together andprevent further movement of lateral separator 110. Movement of handles112, 114 in the direction opposite arrows 130, 132 moves first andsecond portion 22, 42 toward one another, and, if pivoted, movement ofhandles 94, 96 toward one another can pivot first and second portions22, 42 toward one another to reduce working channel 50 for easierremoval of retractor 20 from the incision.

[0066] First and second adjustment mechanisms 102, 104 are provided forsmall incremental adjustment in the rotational positioning of firstportion 22 and second portion 42, respectively. First adjustmentmechanism 102 extends through first tab 134 and engages first couplingmember 98. As first adjustment mechanism 102 is threaded toward firsttab 134, the end of first adjustment mechanism 102 pushes on firstcoupling member 98, causing first coupling member 98 and first handle 94along with first portion 22 to pivot or rotate relative first tab 134.Adjustment mechanism 102 can also engage first coupling member 98 tomaintain first portion 22 in a pivoted or rotated position providedthrough first handle 94. Similarly, second adjustment mechanism 104extends through second tab 136 and engages second coupling member 100.As second adjustment mechanism 104 is threaded toward second tab 136,the end of second adjustment mechanism 104 pushes on second couplingmember 100, causing second coupling member 100 and second handle 96along with second portion 42 to pivot or rotate relative second tab 136.Second adjustment mechanism 104 can also engage second coupling member100 and maintain second portion 42 in a pivoted or rotated positionprovided through second handle 96.

[0067] In use, the resistance to retraction provided by the tissue mayprevent distal ends 24, 44 from separating as far as proximal ends 26,46 when a separation force is applied with lateral separator 110.Rotational separator 92 can be used to move distal ends 24, 44 away fromone another to provide the desired separation between edges 25, 45 alongthe length of first and second portions 22, 42.

[0068] Referring now to FIG. 13, there is shown retractor 20 withanother embodiment instrument 140 for separating first portion 22 andsecond portion 42. Instrument 140 includes a rotational separator 142and a lateral separator 160. Rotational separator 142 is operable torotate or pivot first portion 22 and second portion 42 relative to oneanother about their proximal ends 26, 46 to move distal ends 24, 44 awayfrom one another. Lateral separator 160 is operable to move firstportion 22 and second portion 24 away from one another by separatingproximal ends 26, 46 and distal ends 24, 44 laterally. Rotationalseparator 142 and lateral separator 160 can be operated sequentially topivot then laterally separate, or laterally separate and then pivotfirst and second portions 22, 42. Rotational separator 142 and lateralseparator 160 can also be operated simultaneously to pivot/rotate andlaterally separate first and second portions 22, 42.

[0069] Rotational separator 142 includes a first handle 144 and a secondhandle 146. First handle 144 has a first coupling member 148, and secondhandle 146 has a second coupling member 150. First coupling member 148includes a slot 149 to receive engagement member 32 of first portion 22,and second coupling member 150 includes a slot 151 to receive engagementmember 52 of second portion 42. First and second portions 22, 42 arepivotal or rotatable away from one another by moving first handle 144 inthe direction of arrow 155 toward second handle 146, and by movingsecond handle 146 in the direction of arrow 156 toward first handle 144.Movement of handles 144, 146 in the direction of arrows 155, 156 movescoupling members 148, 150 away from one another to effect the pivotal orrotational movement of first and second portions 22, 42 relative to oneanother.

[0070] Lateral separator 160 includes a first handle 162 and a secondhandle 164. A first connector 166 is pivotally coupled at a mid-portionthereof to first handle 162, and a second connector 168 is pivotallycoupled at a mid-portion thereof to second handle 164. Connectors 166,168 are pivotally coupled at their distal ends to respective ones offirst handle 144 and second handle 146 of rotational separator 142.

[0071] A first link 170 extends between and is pivotally coupled at oneend to first handle 162 and at its opposite end to second connector 168.A second link 172 extends between and is pivotally coupled at one end tosecond handle 164 and at its opposite end to first connector 166. Firstconnector 166 includes a first locking member 152 pivotally coupledthereto that can extend through and releasably engage first handle 144.Second connector 168 includes a second locking member 154 pivotallycoupled thereto that can extend through and releasably engage secondhandle 146. Locking members 152, 154 can selectively engage and maintainthe positioning of handles 142, 144 at any one of a number of positionsto which first portion 22 and second portion 42 have been rotated orpivoted by rotational separator 142.

[0072] First link 170 includes a first slot 174, and second link 172includes a second slot 176. A locking pin 178 extends through slots 174,176 and couples links 170, 172 to one another. To laterally separatefirst portion 22 from second portion 42, locking pin 178 is loosened solinks 170, 172 are movable relative to one another. First handle 162 ismoved in the direction of arrow 180 toward second handle 164, and secondhandle 164 is moved in the direction of arrow 182 toward first handle162. First link 170 pushes outwardly on second coupling member 168 whilesecond handle 164 pulls outwardly on second coupling member 168.Similarly, second link 172 pushes outwardly on first coupling member 166while first handle 162 pulls outwardly on first coupling member 166.Coupling members 166, 168 laterally move connecting portions 148 awayfrom one another. Thus, actuation of handles 162, 164 laterallyseparates the connected first and second portions 22, 42 such that edges25, 45 are laterally displaced relative to one another between proximalends 26, 46 and distal ends 24, 44. Locking pin 178 can then be threadedto clamp link members 170, 172 together and prevent further movement oflateral separator 160. Movement of handles 162, 164 in the directionopposite arrows 180, 182 moves first and second portion 22, 42 towardone another to reduce the spacing therebetween for easier removal ofretractor 20 from the incision.

[0073] In use, the resistance to retraction provided by the tissue mayprevent distal ends 24, 44 from separating as far as proximal ends 26,46 when a separation force is applied with lateral separator 160.Rotational separator 142 can be used to move distal ends 24, 44 awayfrom one another to provide the desired separation between edges 25, 45along the length of first and second portions 22, 42.

[0074] Instrument 140 is positioned over the proximal end opening ofworking channel 50. To provide clear access to working channel 50 forthe surgeon, instrument 140 can be removed from retractor 20, and aguide mechanism 190 can maintain the lateral and rotational positioningof first portion 22 and second portion 42 obtained with instrument 140.Guide mechanism 190 includes a guide member 200 having a slot 202 formedtherein. Guide member 200 extends between first portion 22 and secondportion 42 along one side thereof, and first and second portions 22, 42are coupled thereto. It is also contemplated that a second guide membercould be provided on the other side of retractor 20.

[0075] A first coupling member 192 is movably mounted in slot 202 ofguide member 200 adjacent first portion 22, and a second coupling member214 is movably mounted in slot 202 of guide member 200 adjacent secondportion 42. First portion 22 includes a first ear 208 extending fromcollar 28 pivotally coupled at one end 194 of first coupling member 192.At the other end of first coupling member 192 is a cam locking mechanism196 that is releasably engageable to guide member 200 to maintain thepositioning of first portion 22 along guide member 200. Second portion42 includes a second ear 210 extending from collar 48 that is pivotallycoupled at one end 212 of second coupling member 214. At the other endof second coupling member 214 is a cam locking mechanism 216 that isreleasably engageable to guide member 200 to maintain the positioning ofsecond portion 42 along guide member 200.

[0076] First and second adjustment mechanisms 198, 206 are provided forsmall incremental adjustment in the rotational positioning of firstportion 22 and second portion 42, respectively. First adjustmentmechanism 198 extends through first ear 208 and engages first couplingmember 192. As first adjustment mechanism 198 is threaded toward firstear 208, the end of first adjustment mechanism 198 engages firstcoupling member 192, maintaining first portion 22 in its pivotedposition relative to guide member 200. First adjustment mechanism 198can also be manipulated by the surgeon for small adjustments in thepivotal position of first portion 22 relative to guide member 200 andsecond portion 42. Second adjustment mechanism 206 extends throughsecond ear 210 and engages second coupling member 214. As secondadjustment mechanism 206 is threaded toward second ear 210, the end ofsecond adjustment mechanism 206 engages second coupling member 214 tomaintain second portion 42 in its pivoted position relative to guidemember 200. Second adjustment mechanism 206 can also be manipulated bythe surgeon to make adjustments in the pivotal position of secondportion 42 relative to guide member 200 and first portion 22.

[0077] Referring now to FIG. 14, there is shown another embodimentinstrument 220 for separating first and second portions 22, 42 ofretractor 20. Instrument 220 includes a first handle 222 pivotallycoupled to a second handle 224 about pin 226. First handle 222 includesa distal portion 223 having a coupling member 228. Coupling member 228includes a slot 230 for receiving engagement member 32 of first portion22 therein. Second handle 224 includes a distal portion 225 having acoupling member 232. Coupling member 232 includes a slot 234 forreceiving engagement member 52 of second portion 42 therein. A lockingmember 236 is pivotally coupled at one end to first handle 222, andextends through slot 238 of second handle 224 for releasable lockingengagement therewith.

[0078] In use, instrument 220 is mounted on retractor 20 with couplingmembers 228, 232 in engagement with respective ones of engagementmembers 32, 52. Handles 222, 224 are moved toward one another in thedirection indicated by arrows 240, 242 to move coupling members 228, 232away from one another. In turn, first portion 22 and second portion 42are separated from one another.

[0079] Retractor 20 can be adapted to guide first and second portions22, 42 during separation and to maintain the separation provided withinstrument 220. In the illustrated embodiment, collar 28 of firstportion 22 includes opposite first and second ears 240, 242 extendingbeyond the adjacent edges 25 toward second portion 42. Second portion 42includes first guide member 246 positionable over first ear 240, andsecond guide member 250 positionable over second ear 242. First guidemember 246 includes a slot 248 and second guide member 250 includes aslot 252. A first cam locking mechanism 254 extends through slot 248 andcouples first ear 240 to first guide member 248. A second cam lockingmechanism 256 extends through slot 252 and couples second ear 242 tosecond guide member 250.

[0080] First cam locking mechanism 254 includes a lever 258 that clampsa locking body 260 against first ear 240 and first guide member 246, asshown in FIG. 14. Similarly, second cam locking mechanism 256 includes alever 262 that clamps a locking body 264 against second ear 242 andsecond guide member 250, as shown in FIG. 14. When it is desired to movefirst portion 22 and/or second portion 42, levers 258 and 262 arerotated to release the respective clamped locking body 260, 264,respectively. Instrument 220 can then be used to apply a separationforce, or first and second portions 22, 42 can be moved toward oneanother for easy removal from the incision.

[0081] It is contemplated that guide members 246, 250 can be curved orarcuate to follow the path of coupling members 228, 232 as couplingmembers 228, 232 are separated with handles 222, 224. In this manner,first portion 22 and second portion 42 are simultaneouslypivoted/rotated and laterally separated with instrument 220. It isfurther contemplated that one or more guide members between firstportion 22 and second portion 42 could be configured to provide only alateral separation path or only a rotational separation path. Otherembodiments contemplate guide members which provide a combinedrotational and lateral separation path.

[0082] It is contemplated that for spinal surgery various retractors 20can be provided in a kit with lengths ranging from 20 millimeters to 100millimeters in increments of 10 or 20 millimeters. It is furthercontemplated that retractor 20 can be provided in a kit with varioussized working insertion configurations, such as 14, 16, 18, 20, 21 or 25millimeters for initial insertion width 55. It should be understood,however, that the present invention contemplates that retractor 20 canhave other lengths and diameters and can be provided in a kit withdifferent increments. The appropriate length for retractor 20 willdepend on the depth of the desired surgical location below the skin ofthe patient, the anatomical location of the surgery, and the patient'sanatomy. These factors in retractor selection can be evaluated throughpreoperative planning prior to surgery by x-rays or other known imagingtechnique, and can be adjusted during the surgical procedure ifnecessary since retractors of differing lengths and working channelsizes can be made available.

[0083] Referring to FIGS. 15 and 16, there is shown another embodimentretractor 320. Retractor 320 includes a first retractor portion 322 anda second retractor portion 342. First portion 322 includes a body 323extending between a distal end 324 and an opposite proximal end 326.Second portion 342 includes a body 343 extending between a distal end344 and an opposite proximal end 346. Distal ends 324, 344 can bebeveled or distally tapered to facilitate insertion, althoughnon-beveled ends are also contemplated. First portion 322 can bepositioned adjacent to or mated with second portion 342 along adjacentones of the longitudinal edges 325, 327 of first portion 322 andlongitudinal edges 345, 347 of second portion 342. Other arrangementsbetween the adjacent edges are also contemplated as discussed above. Itis further contemplated that the longitudinal edges can be spaced fromone another in the insertion configuration. A working channel 350 isformed between first portion 322 and second portion 342. Working channel350 extends between and opens at distal ends 324, 344 and proximal ends326, 346.

[0084] Retractor 320 is insertable through skin and tissue of a patientto provide working channel 350 to the surgical site. It is contemplatedthat retractor 320 is inserted through the skin and tissue in aninsertion configuration for working channel 350, such as shown in FIGS.15-18. In the insertion configuration, working channel 350 issubstantially enclosed or circumscribed by first portion 322 and secondportion 342. After insertion into the patient, working channel 350 canbe enlarged by separating first portion 322 and second portion 342 awayfrom one another along an axis 321 extending therebetween. Separation offirst and second portions 322, 342 increases the size of working channel350 from proximal ends 326, 346 to distal ends 324, 344.

[0085] In the insertion configuration of FIGS. 15-18, working channel350 is circumscribed or substantially enclosed by first portion 322 andsecond portion 342. Bodies 323 and 343 can be configured as discussedabove with respect to the bodies of the portions of retractor 20.Working channel 350 can have a size in the insertion configuration thatallows passage of one or more surgical instruments and/or implants tothe surgical location in the patient's body, although smaller sizes arealso contemplated. It may be desirable during surgery to provide greateraccess to the location in the patient's body beyond the locationsprovided through working channel 350 in its insertion configuration.Accordingly, first portion 322 and second portion 342 are movable awayfrom one another along axis 321 to enlarge working channel 350.

[0086] First portion 322 includes body 323 with a semi-cylindrical shapeextending between distal end 324 and proximal end 326. A collar 328extends about proximal end 326, and forms a lip extending about theouter surface of body 323. Second portion 342 includes body 343 having asemi-cylindrical shape extending between distal end 344 and proximal end346. A collar 348 extends about proximal end 346 of second portion 342,and defines a lip extending about the outer surface of body 343. It isfurther contemplated that first and second portions 322, 342 can beprovided with or without a collar and/or a lip. First and secondportions 322, 342 can also be provided with bracket members forengagement with an external arm that supports retractor 320 whilepositioned in the patient.

[0087] Extending from collar 328 of first portion 322 is a firstengagement member 332 having a head portion 336 forming a recess 333therein. Extending from collar 348 of second portion 342 is a secondengagement member 352 having a head portion 356 forming a recess 353therein. Engagement members 332, 352 can be integrally formed with orremovably engaged to the respective collars 328, 348. As discussedfurther below, an instrument for separating first portion 322 and secondportion 342 can be non-releasably or releasably engaged to engagementmembers 332, 352 for application of a separation force to enlargeworking channel 350 by separating first portion 322 and second portion342. Such an instrument could also be releasably or non-releasablyengaged to first portion 322 and second portion 342. Engagement members332, 352 extend laterally from portions 322, 342 to facilitate allowengagement of a separation instrument to engagement members 332, 352without obstructing working channel 350 with the separation instrument.Such an instrument could also maintain first portion 322 and secondportion 342 in the initial insertion configuration during and afterinsertion. The separation instrument can also maintain the enlargedconfiguration for working channel 350 in situ.

[0088] Recesses 333, 353 are adapted to receive engagement arms of theseparation instrument engageable to portions 322, 342. In theillustrated embodiments, engagement members 332, 352 extend laterallyfrom and project proximally above the respective collar 328, 348.Engagement members 332, 352 extend alongside one another and abut oneanother when portions 322, 342 are in their insertion configuration.Other configurations for the engagement members are also contemplated,including engagement members that are non-linear, that extend indirections away from one another when portions 322, 324 are in theirinsertion configuration, and engagement members that do not abut oneanother in the insertion configuration.

[0089] Recesses 333, 353 open laterally to receive respective ones ofthe engagement arms of the separation instrument. Recess 333 includes akeyway opening 335 and a receptacle 337 in communication with opening335. Receptacle 337 is enlarged relative to opening 335, and is shapedto receive a portion of the engagement arm of the separation instrumentpositioned therein. Similarly, recess 353 includes a keyway opening 355and a receptacle 357 in communication with opening 355. Receptacle 357is enlarged relative to opening 355, and is shaped to receive a portionof the engagement arm of the separation instrument positioned therein.Openings 335, 355 and receptacles 337, 357 are open along the proximalsides of the respective engagement members 332, 352 to facilitateplacement of the separation instrument engagement arms therein. Otherconfigurations for the recess 333, 353 are also contemplated, includingrecesses that are enclosed, uniform, or any other suitable configurationto receive a at least a portion of an engagement arm. Still otherembodiments contemplate that engagement members 332, 352 do not includerecesses, but rather are shaped for receipt in or otherwise engage therespective engagement arm of the separation instrument.

[0090] As shown in FIGS. 19 and 20, alignment members 330 can beprovided along one side of one of the engagement members 332, 352(engagement member 352 in the illustrated embodiment.) In theillustrated embodiment, alignment members 330 are rounded protrusionswhich are received in holes provided in the adjacent side of the otherengagement member 332, 352 when engagement members 332, 352 arepositioned adjacent one another. Alignment members 330 maintain firstportion 322 and second portion 342 in longitudinal alignment with oneanother during and after insertion. Other embodiments contemplate otherarrangements for aligning and/or releasably coupling first portion 322and second portion 342 to one another. Examples of such arrangementsinclude dovetail connections, fasteners, threaded coupling members,clamping members, snap rings, compression bands, straps, ball-detentmechanisms, and releasably interlocking cams or tabs, for example.

[0091] Referring to FIGS. 17-20, there is shown a separation instrument360 operable to move first and second portions 322, 342 away from oneanother to enlarge working channel 350. It is contemplated thatseparation instrument 360 includes a lateral separator operable tolinearly move first and second retractor portions away from one anotheralong axis 321. It is further contemplated that separation instrument360 includes at least one rotational separator to pivotally move distalends of first and second portions 322, 342 away from one another alongaxis 321. The lateral and rotational separators can be selectivelyemployed by the surgeon during the surgical procedure to enlarge workingchannel 350 and provide the tissue retraction desired for conducting thesurgical procedure through working channel 350. Enlargement of workingchannel 350 can further retract tissue away from the surgical sitedistal of the distal ends of retractor portions 322, 342 to providegreater access to tissue, bony structures, and other anatomical spaceslocated distally of retractor 320.

[0092] Separation instrument 360 includes a first connection assembly362 movably coupled with a second connection assembly 364. Firstconnection assembly 362 is further coupled to first portion 322, andsecond connection assembly 364 is coupled to second portion 342. Firstand second connection assemblies 362, 264 extend away from first andsecond portions 322, 342 and away from the proximal end opening ofworking channel 350 to facilitate access to working channel 350 duringthe surgical procedure. First and second connection assemblies 362, 364are operable to move first and second portions 322, 342 toward and awayfrom one another to separate tissue. First and second connectionassemblies 362, 364 further include lever assemblies 369, 389,respectively, that are operable to rotate first and second portions 322,342 about their proximal ends to move their distal ends away from oneanother.

[0093] First connection assembly 362 includes a first engagement arm 372coupled to first engagement member 332 of first portion 322 and a firstextension arm 366 extending from first engagement arm 372. A couplingarm 368 is transversely oriented to and extends from the end of firstextension arm 366 opposite first engagement arm 372. A bracket member376 extends from coupling arm 368, and is engageable by a flexible armmounted to a surgical table, for example. First connection assembly 362further includes a first intermediate member 367 fixedly coupled tofirst extension arm 366. First engagement arm 372 is rotatable relativeto intermediate member 367. A first mounting member 375 extends fromfirst engagement arm 372. A first lever arm 374 is pivotally mounted tofirst mounting member 375 and is movable between a locking position,such as shown in FIG. 17, to a pivoting position, as shown FIG. 21.

[0094] Similarly, second connection assembly 364 includes a secondengagement arm 394 coupled to second engagement member 352 of secondportion 342 and a second extension arm 392 extending from secondengagement arm 394. A housing 390 extends from the end of secondextension arm 392 opposite second engagement arm 394. Housing 390includes a passage through which coupling arm 368 is movably received.An adjustment mechanism 399 mounted to housing 390 is engageable tocoupling arm 368 and operable to translate coupling arm 368 in housing390 to effect movement of first and second portions 322, 342 toward andaway from one another along translation axis 321.

[0095] In the illustrated embodiment, coupling arm 368 includes a numberof ratchet teeth 370 formed therealong, which are engageable byadjustment mechanism 399. Adjustment mechanism 399 includes a gear wheel400 with teeth that interdigitate with teeth 370 to effect movement ofcoupling arm 368 in housing 390 as handle 398 is rotated. A lockingmechanism 402 is spring-biased into engagement with teeth 370, andmaintains separation of first and second portions 322, 342 when handle398 is released. Locking mechanism 402 can also be depressed to pivotits engagement end out of engagement with teeth 470 and allow first andsecond portions 322, 342 to move toward one another.

[0096] Second connection assembly 364 further includes a secondintermediate member 393 fixedly coupled to second extension arm 392.Second engagement arm 394 is rotatable relative to intermediate member393. A second mounting member 397 extends from second engagement arm 394alongside second intermediate member 393. Second lever arm 396 ispivotally mounted to second mounting member 397 and is movable between alocking position, such as shown in FIG. 17, to a pivoting position, asshown FIG. 21. Intermediate members 367, 393 can be provided as separatecomponents, or can be integral with the respective extension arm.

[0097] As shown in FIGS. 23-24, first and second engagement arms 372,394 include feet 378, 404, respectively. Feet 378, 404 are slidably andremovably received in respective ones of the recesses 333, 353 ofengagement members 332, 352. In the illustrated embodiment, feet 378,404 include an enlarged outer end portion 379, 405 and a smallercross-section intermediate transition portion 381, 407 extending betweenengagement arms 372, 394 and the enlarged outer end portion 379, 405.Intermediate transition portions 381, 407 are received in theintermediate keyway openings 335, 355, and enlarged outer end portions379, 405 are received in receptacles 337, 357.

[0098] Feet 378, 404 are received recesses 333, 353 in such a mannerthat, as discussed further below, lever arms 374, 396 can effectpivoting of first and second retractor portions 322, 342 by rotatingengagement arms 372, 394 about their respective axes 371, 391,respectively. Furthermore, separation instrument 360 can be easilyremoved from first and second retractor portions 322, 342, facilitatingclean-up of the instrument assembly after the surgical procedure. It isalso contemplated that disposable first and second portions 322, 342 maybe used, or that a set of first and second portions 322, 342 can beprovided in various lengths, shapes and/or sizes from which a surgeonmay select and employ with separation instrument 360

[0099] Intermediate members 367, 393 each include a locking portion,such as engagement portions 426, 414 shown in FIGS. 24, 26, that isengageable with a respective one of the lever arm locking assemblies420, 408. Lever arm locking assemblies 420, 408 each include a pawl 409,421 pivotally coupled to an adjacent one of the mounting members 375,397. For example, as shown in FIGS. 24 and 26, lever arm lockingassembly 420 includes a pivot pin 422 mounted to mounting member 375about which pawl 421 can be pivoted. Similarly, lever arm lockingassembly 408 includes a pivot pin 410 mounted to mounting member 397about which pawl 409 can be pivoted. Intermediate members 367, 393 eachinclude respective ones of engagement portions 426, 414 to which thelocking members 420, 408 are engageable to maintain a pivoted positionof first and second portions 322, 342.

[0100] For example, as shown in FIG. 26 relative to intermediate member367, there is provided an engagement portion 426 along intermediatemember 367 oriented toward pawl 421. Pawl 421 includes a proximal handleportion 423 and a distal engagement end 424. Distal engagement end 424is positionable in at least one the recesses provided between teeth 428to maintain a pivoted position of first portion 322. As lever arm 374 isrotated counterclockwise to pivot the distal end of retractor portion322 away from the distal end of retractor portion 342, pawl 421 movesabout engagement portion 426 for engagement there with at a locationcorresponding to the position of the pivoted retractor portion 322.

[0101] Other embodiments contemplate that intermediate members 367, 393are movable as the respective retractor portion is pivoted. In suchembodiments, the pawl 409, 421 does not move or rotate with rotation ofengagement arm, but rather remains fixed for engagement with theadjacent engagement portion of the respective intermediate member 367,393 as it is rotated.

[0102] In FIG. 24, first lever arm 374 is shown pivoted on mountingmember 375 to its pivoting position, and second lever arm 396 is shownpivoted on mounting member 397 to its locking position. In the lockingposition, lever arm 396 includes a protrusion 406 that is engageable tothe proximal handle portion of pawl 409. In the engaged position,proximal handle portion 413 cannot be moved toward mounting member 397to remove its engagement end 412 from the teeth along engagement portion414 of intermediate member 393. Accordingly, the pivoted position ofsecond retractor portion 342 is locked by the positioning of lever arm396 in its locking position, and second retractor portion 342 cannot bemoved unless lever arm 396 is moved to its pivoting position.

[0103] In FIG. 24 first lever arm 374 is shown in its pivoting position,and includes a protrusion 418 extending from first lever arm 374 that ispositioned out of contact with pawl 421. In this position, pawl 421 canbe pivoted about pin 422 to remove engagement end 424 from between teeth428. Lever arm 374 can then be manipulated to pivot first retractorportion 322 to a desired angular position along axis 321. As lever arm374 is pivoted, locking member 420 is moved therewith into alignmentwith another space between teeth 428. When the desired orientation offirst portion 322 is obtained, then proximal handle portion 423 can bereleased, and locking member 420 can be spring biased or otherwise movedto engage engagement portion 426 and maintain the pivoted position offirst portion 322. Lever arm 396 can then be pivoted on mounting member375 to its locking position where protrusion 418 engages pawl 421 toprevent it from being released from engagement portion 426.

[0104] Referring to FIGS. 27-28, there is shown a first intermediateretractor assembly 450 engageable to separation instrument 360.Intermediate retractor assembly 450 includes a retractor blade 452positionable between first and second retractor portions 322, 342 toretract and/or maintain tissue from the working channel 350 in adirection transverse to axis 321. In one operative approach to thespine, retractor 320 is oriented so that retractor portions 322, 342 aremovable along axis 321 oriented in the direction of the central axis ofthe spinal column, and blade 450 is positioned medially or adjacent tothe spinal column relative to the other retractor blade portions 322,342. Other operative orientations in the incisions for the retractorblades and retractor portions are also contemplated.

[0105] First intermediate retractor assembly 450 includes blade 452extending between a distal end 454 and a proximal end 456. As shown inFIG. 28, distal end 454 is curved away from the working channel 350, andcan rest upon bone or other tissue when positioned in the retractedincision. Blade 452 can include a flat profile between distal end 454and proximal end 456, or include a convex curvature about itslongitudinal axis or along its longitudinal axis. Blade 452 can also beprovided as a single member, or in one or more components movablerelative to one another to lengthen or shorten blade 452.

[0106] A linking arm 458 is transversely oriented to and extends fromproximal end 456 of blade 452. Opposite blade 452 there is provided anengaging portion in the form of first and second hook members 462, 464.Lower hook member 464 can be positioned about coupling arm 368 ofseparation instrument 360. Linking arm 458 has a length such that thepressure from the tissue at the incision against blade 452 firmly holdshook member 464 against coupling arm 368. Upper hook member 462 canserve as a handle to facilitate placement of lower hook member overcoupling arm 368 or removal of intermediate retractor assembly 450.Other arrangements for securing blade 452 to coupling arm 368 are alsocontemplated, such as fasteners and interfitting components, forexample.

[0107] First intermediate retractor assembly 450 is further mountable bya second intermediate retractor assembly 470, as shown in FIGS. 29 and30. Second intermediate retractor assembly 470 includes a blade 472extending between a distal end 474 and a proximal end 476. Distal end474 and the blade portion extending therefrom can be configured asdiscussed above with respect to blade 452. A second linking arm 478extends from proximal end 476, and includes an engagement foot 480opposite blade 472. Engagement foot 480 is removably mountable tolinking arm 458 of first intermediate retractor assembly 450.

[0108] First linking arm 458 includes slotted holes 460 (FIGS. 27-28)extending therethrough adapted to receive pins (not shown) extendingfrom a lower surface of foot 480 of second linking arm 478. The pins canbe provided with enlarged heads positionable in the enlarged portions ofslotted holes 460, and are slidable to the narrowed ends of the slottedholes 460 so that the heads are captured in slotted holes 460. In theillustrated embodiment, the narrowed portions of the slotted holes 460extend opposite retractor blade 472 so that the pressure from the tissueabout the incision pushing against blade 472 maintains the pins of foot480 in the narrowed end portions of slotted holes 460.

[0109] Second linking arm 478 includes offset portions 486 extendingtransversely to first linking arm 458. Offset portions 486 are linked byan offset member 479 extending therebetween. Offset member 479 can beprovided with an arcuate profile to extend around the respectiveadjacent retractor portion 322, 342 so as to not obstruct access toworking channel 350. Retractor blade 472 can maintain tissue retractionand provide protection to tissue located along the side of the workingchannel opposite retractor blade 452. First and second intermediateretractor assemblies 450, 470 provide the surgeon with additionaloptions during the surgical procedure with regard to tissue retractionand protection that can be readily employed with separation instrument360 engaged to retractor 320.

[0110] In one surgical procedure, retractor 320 is engaged to separationinstrument 360 and inserted in an incision. Retractor 320 can beadvanced over one or more dilators dilating an incision, or directlyinto the incision. Separation instrument 360 is then operated tolinearly move retractor portions 322, 342 away from one another alongaxis 321 to enlarge working channel 350. One or both of the lever arms374, 396 can be moved to its pivoting position and manipulated to pivotthe respective retractor portion 322, 342. When the retractor portionhas been pivoted, the respective lever arms are moved to their lockingposition so that the protrusion extending therefrom engages the adjacentpawl 409, 421 to maintain the pawl in engagement with adjacentengagement portion 414, 426.

[0111] When the desired separation has been obtained, the surgeon hasthe option to select first intermediate retractor assembly 450. Blade452 is positioned in the incision between the separated first and secondretractor portions 322, 342, and linking arm 458 is secured to couplingarm 368. The surgeon has the further option of selecting secondintermediate retractor assembly 470, and positioning blade 472 in theincision opposite blade 452. Linking arm 478 can then be secured tolinking arm 458. Further adjustment of the spacing and orientation ofretractor portions 322, 342 can be completed with separation instrument360 and/or lever arms 374, 396.

[0112] It is further contemplated that retractor portions 322, 342 neednot be separated from one another linearly, but are separated during thesurgical procedure only by pivoting one or both of them along axis 321.Once the working channel 350 provides the desired access, the surgeoncan remove bone, tissue, disc material, or other matter throughretractor 320. Implants, such as fusion devices, screws, plates, rods,artificial discs, bone growth material, and other repair devices ortherapeutic substances can be delivered through retractor 320 to thedesired site in the patient's body.

[0113] While the invention has been illustrated and described in detailin the drawings and foregoing description, the same is to be consideredas illustrative and not restrictive in character, and that all changesand modifications that come within the spirit of the invention aredesired to be protected.

What is claimed is:
 1. A retractor assembly for percutaneous surgery ina patient, comprising: a first retractor portion having a proximal endand a distal end and being positionable in an incision; a secondretractor portion having a proximal end and a distal end and beingpositionable in the incision opposite said first retractor portion, saidfirst and second retractor portions defining an axis extendingtherebetween; a separation instrument coupled between said proximal endsof said first and second retractor portions and being offset to one sideof said axis, said separation instrument being operable to move saidfirst and second retractor portions along said axis from an insertionconfiguration wherein said first and second retractor portions areadjacent one another to a second configuration wherein said first andsecond portions are separated from one another; and an intermediateretractor assembly removably mountable to said separation instrument,said intermediate retractor assembly including a linking arm extendingfrom said separation instrument toward said first and second retractorportions to a retractor blade, said retractor blade being transverselyoriented to said linking arm and being positionable in the incisionbetween said first and second retractor portions when said linking armis mounted to said separation instrument and said first and secondretractor portions are in said second configuration.
 2. The assembly ofclaim 1, wherein separation instrument includes a first connectionassembly connected to said first retractor portion and a secondconnection assembly connected to said second retractor portion, saidfirst and second connection assemblies being movably coupled with oneanother.
 3. The assembly of claim 2, wherein said first connectionassembly includes a first engagement arm engaged to said first retractorportion and extending transversely to said axis and said secondconnection assembly includes a second engagement arm engaged to saidsecond retractor portion and extending transversely to said axis.
 4. Theassembly of claim 3, wherein said first and second retractor portionseach include an engagement member extending therefrom engageable byrespective ones of said engagement arms.
 5. The assembly of claim 4,wherein said first and second engagement members each include a recessfor removably receiving a foot extending from an end of said engagementarm engaged thereto.
 6. The assembly of claim 5, wherein each of saidrecesses includes a keyway opening at an end of said respectiveengagement member to receive a stern extending between said respectiveengagement arm and said foot, each of said recesses further including anenlarged receptacle in communication with said keyway opening sized andshaped to non-rotatably receive said respective foot therein.
 7. Theassembly of claim 2, wherein each of said connection assemblies includesan engagement arm coupled to said respective said retractor portion, anextension arm extending from said engagement arm, said engagement armbeing rotatable relative to said extension arm to pivot said distal endof said respective retractor portion along said axis.
 8. The assembly ofclaim 7, further comprising a lever arm assembly coupled to each of saidengagement arms, said lever arm assemblies each including a lever armmanipulatable to rotate said respective engagement arm about an axisthereof and thereby pivot said distal end of said retractor portionengaged thereto.
 9. The assembly of claim 8, further comprising a leverarm locking assembly engaged to each of said lever arm assembliesoperable to maintain a rotated position of said engagement arm coupledto said lever arm assembly.
 10. The assembly of claim 9, wherein saidlever arm locking assemblies each include a pawl pivotally coupled tosaid respective lever arm assembly, said pawl being engageable with anengagement portion along an adjacent one of said extension arms tomaintain said rotated position thereof.
 11. The assembly of claim 10,wherein each of said pawls and said lever arms is pivotally coupled to amounting member extending from said adjacent engagement arm.
 12. Theassembly of claim 11, wherein each of said lever arms is movable betweena pivoting position and a locking position, and in said pivotingposition each of said lever arms extends from said mounting member andis manipulatable to rotate said adjacent engagement arm and in saidlocking position each of said lever arms engages said pawl and lockssaid pawl in engagement with said engagement portion of said adjacentextension arm.
 13. The assembly of claim 12, wherein each of said leverarms includes a protrusion that engages a proximal handle portion ofsaid pawl to bias an opposite engagement end of said pawl in engagementwith said engagement portion.
 14. The assembly of claim 7, furthercomprising an intermediate member between each of said engagement armsand said extension arms, each of said engagement arms being rotatablerelative to said intermediate member, each of said intermediate membersincluding an engagement portion engageable to maintain a rotatedposition of said engagement arm relative to said intermediate member.15. The assembly of claim 7, wherein one of said connection assembliesincludes a coupling arm extending transversely to said extension armthereof, and the other of said connection assemblies includes a housingat an end of said extension arm thereof, said coupling arm beingreceived in said housing and engageable with an adjustment mechanismoperable to move said first and second retractor portions along saidaxis.
 16. The assembly of claim 15, wherein said coupling arm includes anumber of ratchet teeth extending therealong, and said adjustmentmechanism includes a gear wheel engageable with said ratchet teeth andoperable to effect movement of said coupling arm in said housing therebymoving said first and second retractor portions along said axis.
 17. Theassembly of claim 1, wherein: said separation instrument includes firstand second engagement arms extending from respective ones of said firstand second retractor portions and a coupling arm extending between saidfirst and second engagement arms; and said linking arm of saidintermediate retractor assembly is removably engageable to said couplingarm.
 18. The assembly of claim 17, further comprising a secondintermediate retractor assembly engageable with said intermediateretractor assembly, said second intermediate retractor assemblyincluding a second retractor blade positionable in the incision oppositethe first retractor blade and between the first and second retractorportions when the first and second retractor portions are separated fromone another.
 19. The assembly of claim 18, wherein said secondintermediate retractor assembly includes a second linking arm coupled tosaid linking arm and extending to said second retractor blade.
 20. Theassembly of claim 19, wherein said second linking arm includes a firstoffset portion extending from said linking arm of said intermediateretractor assembly to an offset member of said second intermediateretractor assembly, said offset member extending along one of said firstand second retractor portions and being offset from a proximal extensionof a working channel formed between said first and second retractorportions, said offset member extending to a second offset portionopposite said first offset portion, said second offset portion extendingfrom said offset member to said second retractor blade.
 21. The assemblyof claim 1, wherein said first retractor portion includes a collar aboutsaid proximal end thereof and said second retractor portion includes acollar about said proximal end thereof, each of said collars includingan engagement member extending laterally therefrom for engagement bysaid separation instrument.
 22. The assembly of claim 21, wherein: oneof said engagement members of said first retractor portion and saidretractor second portion includes alignment members extending towardsaid engagement member of the other of said first retractor portion andsaid second retractor portion; and said engagement member of the otherof said first retractor portion and said second retractor portionincludes receptacles for receiving respective ones of said alignmentmembers.
 23. The assembly of claim 1, wherein each of said first andsecond retractor portions includes a semi-cylindrical body.
 24. Theassembly of claim 1, wherein: said first retractor portion includesopposite edges extending therealong between said proximal end and saiddistal end thereof; said second retractor portion includes oppositeedges extending therealong between said proximal end and said distal endthereof; wherein a working channel between said first and secondretractor portions is enclosed when said opposite edges of said firstretractor portion are adjacent respective ones of said opposite edges ofsaid second retractor portion; and wherein when said working channel isenlarged said opposite edges of said first retractor portion areseparated from respective ones of said opposite edges of said secondretractor portion.
 25. The assembly of claim 24, wherein said oppositeedges of said first retractor portion abut with an adjacent one of saidopposite edges of said second retractor portion when said workingchannel is substantially enclosed by said first and second retractorportions.
 26. A retractor assembly for percutaneous surgery in apatient, comprising: a first retractor portion having a proximal end anda distal end and being positionable in an incision; a second retractorportion having a proximal end and a distal end and being positionable inthe incision opposite said first retractor portion, said first andsecond retractor portions defining a first axis extending therebetween;and a separation instrument coupled between said proximal ends of saidfirst and second retractor portions and being offset to one side of saidfirst axis, said separation instrument being operable to move said firstand second retractor portions away from one another along said firstaxis, said separation instrument including a first engagement armextending from said proximal end of said first retractor portion along asecond axis transverse to said first axis and a second engagement armextending from said proximal end of said second retractor portion alonga third axis transverse to said first axis, wherein said engagement armseach include a portion adjacent said respective retractor portion thatis rotatable about said respective axis thereof to pivot said respectiveretractor portion engaged thereto about its proximal end.
 27. Theassembly of claim 26, wherein said separation instrument furthercomprises a coupling arm extending between said engagement arms and anadjustment mechanism engaged to said coupling arm to couple saidengagement arms and said retractor portions to one another for linearmovement in a direction of said first axis and transversely to saidsecond and third axes.
 28. The assembly of claim 27, further comprisinga first intermediate retractor assembly mountable to said separationinstrument, said first intermediate retractor assembly including alinking arm mountable at one end to said coupling arm of said separationinstrument and extending from said one end to a retractor blade at anopposite end, said retractor blade being transversely oriented to saidlinking arm and being positionable in the incision between said firstand second retractor portions when said linking arm is mounted to saidseparation instrument and said first and second retractor portions areseparated from one another.
 29. The assembly of claim 28, furthercomprising a second intermediate retractor assembly engageable with saidfirst intermediate retractor assembly, said second intermediateretractor assembly including a second retractor blade positionable inthe incision opposite the first retractor blade and between the firstand second retractor portions when the first and second retractorportions are separated from one another.
 30. The assembly of claim 29,wherein said second intermediate retractor assembly includes a secondlinking arm coupled to said linking arm of said first intermediateretractor assembly and extending to said second retractor blade.
 31. Theassembly of claim 30, wherein said second linking arm includes a firstoffset portion extending from said linking arm of said firstintermediate retractor assembly to an offset member of said secondintermediate retractor assembly, said offset member extending along oneof said first and second retractor portions and being offset from aproximal extension of a working channel formed between said first andsecond retractor portions, said offset member extending to a secondoffset portion opposite said first offset portion, said second offsetportion extending from said offset member to said second retractorblade.
 32. The assembly of claim 26, wherein said first and secondretractor portions each include an engagement member extendingtransversely therefrom, said engagement members being engageable by arespective one of said engagement arms, wherein said engagement membersextend along respective ones of said first and second axes when engagedto said respective engagement arm.
 33. The assembly of claim 32, whereinsaid first and second engagement members each include a recess forremovably receiving a foot extending from an end of said respectiveengagement arm.
 34. The assembly of claim 26, further comprising a leverarm coupled to said rotatable portion of each of said engagement arms,said lever arms being manipulatable to rotate said rotatable portionabout said respective axis of said engagement arm thereby pivoting saidretractor portion engaged thereto.
 35. The assembly of claim 34, furthercomprising a lever arm locking assembly on said rotatable portion ofeach of said engagement arms, said lever arm locking assemblies eachbeing releasably engageable with an engagement portion of a second,non-rotatable portion of said engagement arm.
 36. The assembly of claim35, wherein said lever arm locking assemblies each include a pawlmounted to said rotatable portion of each of said engagement arms, saidpawls each being engageable with said engagement portion.
 37. Theassembly of claim 36, wherein said pawls are each pivotally coupled to amounting member extending from said rotatable portion of said respectiveengagement arm.
 38. The assembly of claim 37, wherein each of said leverarms is movable between a pivoting position and a locking position, andin said pivoting position said lever arms extend from said respectivemounting member and are manipulatable to rotate said rotatable portionof said engagement arm and in said locking position said lever arms eachengage said respective pawl and lock said pawl in engagement with saidengagement portion.
 39. The assembly of claim 38, wherein each of saidlever arms includes a protrusion that engages a proximal handle portionof said respective pawl to bias an opposite engagement end of said pawlin engagement with said engagement portion.
 40. The assembly of claim27, wherein each of said engagement arms includes an extension armextending between said coupling arm and said rotatable portion, saidextension arm being fixed relative to said rotatable portion.
 41. Theassembly of claim 40, further comprising an intermediate member betweeneach of said rotatable portions and said extension arms, saidintermediate members each including an engagement portion thereon forengagement by a lever arm locking assembly to maintain a pivotedposition of said respective retractor portion.
 42. The assembly of claim27, wherein said rotatable portion of each of said engagement armsincludes a lever arm mounted thereto, said lever arms each being offsetfrom said proximal end of said respective retractor portion along saidaxis of said respective engagement arm.
 43. A retractor assembly forpercutaneous surgery in a patient, comprising: a first retractor portionhaving a proximal end and a distal end and being positionable in anincision; a second retractor portion having a proximal end and a distalend and being positionable in the incision opposite said first retractorportion, said first and second retractor portions defining a first axisextending therebetween; and a separation instrument coupled between saidproximal ends of said first and second retractor portions and beingoffset to one side of said axis, said separation instrument including afirst engagement arm extending from said proximal end of said firstretractor portion along a second axis transverse to said first axis anda second engagement arm extending from said proximal end of said secondretractor portion along a third axis transverse to said first axis,wherein said engagement arms each include a portion adjacent saidrespective retractor portion that is rotatable about said respectiveaxis thereof and a lever arm extending from said rotatable portionoperable to rotate said rotatable portion and pivot said respectiveretractor portion engaged thereto about its proximal end.
 44. Theassembly of claim 43, wherein said separation instrument is structuredto move said first and second retractor portions linearly away from oneanother along said first axis.
 45. The assembly of claim 44, whereinsaid separation instrument further comprises a coupling arm extendingbetween said engagement arms and an adjustment mechanism engaged to saidcoupling arm to couple said engagement arms and said retractor portionsto one another for linear movement in a direction of said first axis andtransversely to said second and third axes.
 46. The assembly of claim43, further comprising a mounting member extending from each of saidrotatable portions, wherein each of said lever arms is pivotally mountedto a respective one of said mounting members.
 47. The assembly of claim43, further comprising a lever arm locking assembly mounted to each ofsaid engagement arms operable to maintain a rotated position of saidengagement arms.
 48. The assembly of claim 47, wherein said lever armlocking assemblies each include a pawl mounted to said rotatable portionof each of said engagement arms, said pawls each being engageable withan engagement portion along a non-rotatable portion of said respectiveengagement arm.
 49. The assembly of claim 48, wherein said pawls andsaid lever arms are each pivotally coupled to a mounting memberextending from said rotatable portion of said respective engagement arm.50. The assembly of claim 49, wherein each of said lever arms is movablebetween a pivoting position and a locking position, and in said pivotingposition said lever arms extend from said respective mounting member andare manipulatable to rotate said respective rotatable portion of saidengagement arm and in said locking position said lever arms engage saidrespective pawl and lock said pawl in engagement with said engagementportion.
 51. The assembly of claim 50, wherein each of said lever armsincludes a protrusion that engages a proximal handle portion of saidpawl adjacent thereto to bias an opposite engagement end of said pawl inengagement with said engagement portion.